Image sensors are used in cameras and other imaging devices to capture images. In a typical imaging device, light enters at one end of the imaging device and is directed to an image sensor by an optical element such as a lens. In most imaging devices, one or more layers of optical elements are placed before and after the aperture stop to focus light onto the image sensor. Recently array cameras having many imagers and lenses have been developed. In most cases, multiple copies of the optical elements must be formed laterally for use in array cameras.
Conventionally, optical arrays can be formed by molding or embossing from a master lens array, or fabricated by standard lithographic or other means. However, the standard polymer-on-glass WLO and monolithic lens WLO manufacturing techniques have so far not been adapted for the specific high performance requirements of array cameras. In particular, some technical limitations of conventional WLO-processes need to be reduced, such as, for example, minimum substrate thickness requirements, inflexibility of where to place the aperture stop, accuracy, etc. The flexibility of such choices or processes needs to be increased in order to meet the high demands by array cameras otherwise such WLO techniques cannot be used to manufacture array cameras. Accordingly, a need exists for fabrication processes capable of accurately forming these arrays and for optical arrangements that give an increased flexibility in manufacturing so that the image processing software of these new types of array-type cameras can take advantage to deliver superior image quality at the system level.